09.17.2015  |  News

Late Summer Preparations for Fall Rain


September is already half over, and for those of us in the Pacific Northwest, this means the rainy season is just around the corner. In Washington State, facilities operating under the Industrial Stormwater General Permit (ISGP), are required to sample the stormwater discharge from the first fall storm event each year. According to the ISGP, the “first fall storm event” means the first time on or after October 1st of each year that precipitation occurs and results in a stormwater discharge from a facility. In Oregon State, the 1200-Z and 1200-COLS general stormwater discharge permits require facilities to collect two samples, at least 14 days apart, on or before December 31st.

We have expanded upon our May 2015 post “Simple Activities for Stormwater Improvements” and have assembled a list of late-summer preparations that may help with stormwater quality, particularly for those that are required to sample a first flush type event. The permits require many of these activities to be conducted year-round, but the first overcast skies of the season can serve as a good reminder to make sure you’re in compliance for the year to come.

  • Hand Sweep – On days that the street sweeper is coming, use a leaf blower and broom ahead of the sweeper to clean out those hard to reach areas the sweeper will normally miss. Don’t forget to hand sweep around the catch basins (especially if they are in a low spot the sweeper can’t get to), material staging areas, corners in loading docks, and around outdoor equipment and tanks.
  • Clean out catch basins and replace catch basin inserts, especially if this wasn’t completed at the end of the rainy season.
  • Inspect stormwater conveyance piping. If sediment accumulation is visible, consider having the lines cleaned/power washed and the resulting debris vacuumed out.
  • Perform maintenance on stormwater treatment units – inspect for trash and debris and remove it, change filter media if needed, replace unhealthy or dead vegetation and add new mulch in swales.
  • Move equipment and operations under cover. This can include temporary covers, such as tarping. Be sure to include the inspection and maintenance of temporary covers in your monthly inspection route.
  • Perform preventative maintenance of equipment and vehicles that are staged outdoors.
  • Order sampling kits from the lab so coolers and bottles are on hand. Place inspection forms, chain of custody, bottle labels, and pen inside a gallon-size zip top bag. Fill out information like sample names and required analyses on the chain of custody forms while you’re inside in a dry location. Sample date and time should be completed when the samples are taken.
  • Check and organize your sampling and field pH testing equipment. This is a good opportunity to train new staff and refresh existing staff on proper sampling procedures and responsibilities.
  • Review your SWPCP or SWPPP to confirm that it is current and updated with any changes to the facility that may have occurred over the summer.

Also, a quick reminder for Washington ISGP Permittees that either directly or indirectly discharge to a Puget Sound Sediment Cleanup Site through a stormwater drainage system: Accumulated solids must be removed from storm drain lines (including inlets, catch basins, sumps, conveyance lines, and oil/water separators) owned or controlled by the Permittee at least once prior to October 1, 2016. Additionally, Washington ISGP permittees must sample and analyze storm drain solids in accordance with Table 8 in the permit at least once prior to October 1, 2016.


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